If by RCA female adapter you are refering to the type of input on the ep 500 the yes it accepts a rca type connector. This will come from your sub out on your reciever and will connect with a male/male cable.

The EP350 and up come with XLR plugs that take a 1/4" (electrically separate)->RCA adapter to provide a standard unbalanced input. Axiom made this change awhile back to cut down on fixes due to busted off RCA connectors.